To further improve the existent machines with respect to their sensitivity and shortening of the dead-time of the stopped-flow machine. In addition, to build a laser heating temperature-jump machine and a slow heat exchange temperature-jump machine to cover the nanosecond and second range respectively. To further explore the physical and chemical properties of the unadenylylated and adenylylated glutamine synthetase with respect to their catalytic and regulatory functions. In particular, we will utilize the stopped-flow technique to study the kinetics of inhibition and catalysis at high enzyme level such as that present in vivo. To study the kinetics and mechanism of DNA-repressor interaction utilizing the tryptophan fluorescence of the repressor.